Zipp have explained the small increase - they changed the carbon layup with the latest generation, then when weighing them realised they were slightly heavier so updated the weights on their website. But yes, still quite a bit lighter than the hooked versions of those wheels.
Worth pointing out that the ETRTO standards apply to all wheels, not just hookless. I.e. Riding a 28mm tyre on a 25mm IW hooked rim is still outside the standard. There has always been some onus on cyclists to figure out the right components/spares for their bike, whether thatās different wheel diameters (Iāve had a friend puncture a 700C wheel and pull a 650 tube out of his saddle bag before!), widths, pressures, multiple drive train speeds, etc.
Agree the bike industry could do a much better job of labelling and explaining things to make it easier for the consumer. Concern for me is Iāve had or been told of multiple conversations with bike shops and mechanics who either donāt know about or are deliberately not following manufacturer or ETRTO recommendations/limits. So itās not even just the consumer who is confused. And that makes me suspect that even world tour riders and mechanics might not follow those recommendations.
You sure about that? Everything I have seen and read about it has been soecifically related to hookless.
I noticed one link to what seemed to be youtubers presenting actual data on rate of blowoffs. Is there anything else? I still find all of this incredibly far fetched, especially the psi being thrown around here.
Granted this is a single case, and not hookless. But I generally have to inflate to 80-90 psi just to get beads to get out of the center channel and seat on the rim shelf. I just have a seriously hard time believing, hookless or not, that any tire is in danger of blowing off a rim at 80 psi.
And note, Iām not talking about any standard when talking about setting up properlyā¦
Why do you keep conflating different issues?
Well, Iām sure your ābeliefsā carry more weight than an organization who tests and develops standards specifically for tires. What do they know anyway?
It would be interesting to know what pressures us higher weight riders are using on their hookless set upsā¦ some of the ācalculatorsā or recommended pressures seem far to high to me anyway. Some may as well say āyouāre too fat so donāt bother!ā
I know there are a lot of variables, but for me total weight including me, bike, clothing, full drinks bottle and tool kit is approx. 100kg. 28mm tyres on 22.4mm internal width rim. 70psi front and rear, not had an issue yet.
Yes, sure about it. The conversation has been focused on hookless because Zipp and Enve have been the main manufacturers insisting that their testing allows them to state that 28mm tyre on a 25mm rim is fine even if not compliant with ETRTO. And donāt think any of the hooked wheels have gone as wide as 25mm yet - e.g. Rovals have pretty wide external runs but internal width is still 21mm. DT Swiss are 20mm.
My point really was that even with hooked the consumer still has to buy the right tyre e.g. You canāt (or at least shouldnāt) run a 23mm tyre on a 21mm IW hooked rim. So the general concept of customers having to get their heads around what tyres and pressures are compatible with their wheels isnāt anything new. Which has no bearing on whether a 28mm tyre on a 25mm hooked rim is a good idea!
Nor should there beā¦l.That is within the specifications.
False. ETRTO and ISO, the professional engineers that are experts in this area, specify a max adoptable pressure of 72.5 psi (5 bar). They also allow a safety factor of only 1.1 for blowoff pressure. That means that itās considered OK for the tire to blowoff at 80psi per the standard. Now keep in mind thatās a static test (no impacts) performed in a lab (no sun softening up the rubber) with brand new, clean parts (no soap residue from getting tire on rim, no corrosion, etc). There are factors that affect the failure pressure that arenāt included and might not even be known. And that all assumes rim and tire quality control is very good. Quality spills happen. Do you feel safe with that margin? I donāt.
Then also consider that many people have crappy air pressure gauges that read off by up to 20%.
Contrast that with the 1.5 safety factor for blowoff pressure that is specified for hooked rims. And also consider that with road hookless you have to use a pressure much closer to the max then you do with hooked, just to prevent pinch flats.
Those are facts. Hard data that does not rely on any anecdotes.
Itās true that the spec should be considered minimum criteria and rim makers are free to design too much better safety factors. But itās also true that some (especially Zipp) are violating this minimum spec with regards to tire vs rim width.
Everyone that does not have an interest in seeing you hookless rims that has weighed in on the hookless debate says itās not as safe as it should be for road use. The only ones pushing it have a significant financial conflict of interest or are only armchair engineers.
Honestly this thread is a GREAT example of the confusion thatās been created on this topic. Presumably most folks here are fairly knowledgeable, but itās just been a parade of conjecture, anecdote and misinformation.
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The only real concern with hookless is rim/tire combos where the nominal tire size approaches the rim width. So to all the folks posting that theyāve been running 28-30mm tires on 21-23mm hookless rims (e.g.) without issues, no shit, thatās to be expected. Hookless works great on MTB (tires much fatter than rims) or for that matter cars (everything super over-built relative to bikes.)
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You can see the list of currently approved ETRTO rim/tire combinations here.
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That list applies to both hooked and hookless. As Josh Poertner points out (probably the 10th time this article has been linked to) this makes little sense, as he and others have observed big differences in blow-off behavior between the two designs. He advocates for separate standards for hooked vs. hookless.
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The bottom line issue is that there are legit aero and ride quality gains to running a tire thatās nearly as wide as the inner width of the rim, e.g. a 28mm tire on a 25mm inner-width rim, or even Joshās suggested 32mm tire on a 29mm rim. These combos seem to be very safe with hooked rims, but are concerningly close to failure at higher PSI on hookless. But thatās the only real concern here: as rims get wider to reap performance gains, hookless becomes a problem.
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I personally wouldnāt run a 28mm tire on a 25mm hookless rim, even though this is an ETRTO approved setup (EDIT: WAS an ETRTO approved combo, has since been updated to not-approved though still approved by Zipp and ENVE, WTF.) Your 23mm hookless rims are probably fine, as long as you donāt go smaller than say a 28mm tire. Whether āprobably fineā is a safety margin youāre OK with given potential consequences of failure at high speed is up to you.
That is not an approved ETRTO combination. It is a combination that Zipp and EMVE approve, however.
Correction. That WAS an approved combo in the 2022 ETRTO update that was then modified in the 2023 update. Now, 29mm is the smallest allowed tire on 25mm IW rims. Latest spec is below.
Think of all the consumers running around with suddenly out of spec combos. Itās the fricking Wild West with road hookless tubeless.
BTW, the ETRTO spec is not freely published. Isnāt it awesome when a spec that is for consumer safety isnāt available to consumers? What the hell.
Thanks, good point and updated my post. And yeah, what a clusterf*ck.
I thought that was haunting me since the beginning of this talk.
Thomas de Gendtās case, for instance. A hooked rim would have kept the tire in place. It appears to me that he broke the rim badly to the extent that the insert was cut in two. So, is it really related to the safety of hookless or hooked?
Because, honesty, if you smash your wheel, sorry, but thereās no ERTRO, ENVE, ZIPP, Continental, Josh or whatever thesis one wants to ventilate able to keep the tire in place. Maybe tubular?
Itās not false just because the specs donāt demand a test for it.
Itās a fact that most good wheel tyre combos will withstand 100psi+
Itās been tested many times by many people at this point. Iāve personally tested GP5000STR 28&30, ASTR 32, Pirelli Cinturato 32, Corsa Pro 28&30 at 100psi across Zipp 303S and 353nsw.
I do this with every new tyre and leave it over night, to rule out an out of spec tyre.
There is nothing to indicate deGendt broke his wheel. The other Lotto rider in Strade, however, did appear to break his wheel.
Nothing except the team, tyre manufacturer and rim manufacturer saying thatās what happenedā¦.
No, that is NOT what they saidā¦
They said he hit a rock and that caused damage to the tire, not the wheel. And de Gendt himself says he did not hit anything.
Also two more things to note about all of this:
The Zipp 353 NSW rims seem to be particularly associated with blowouts. Itās just anecdotal data, but I would be particularly cautious with those.
The issue here is the specific combination of all four factors:
- Hookless
- Tubeless
- Tires close in actual width to rim internal width
- Road use
If any of those factors is missing, you have a greater safety factor. If you have hookless rims that you donāt have faith in, use them on gravel with a wider tire or run tubes. Tubes actively press the tire bead against the rim wall so it takes 30% more pressure to create a blowoff.
If you are trying to compare to gravel or MTB use, donāt. The tires used there are much wider than the rims and the forces on the system are different. Some of the cyclic fatigue tests for bikes specify more severe forces for road use than for MTB use. Apples and oranges.
And donāt compare a fricking thing about car and bicycle tires/rims. Completely different designs of the tire structure (rigid radial) and not possible to mount tires by hand roadside.
Our team is treating the situation with the utmost urgency. It was their assessment that the nature of the impact would have caused severe damage to the tire and rim regardless of the rim design. Images circulating online indicate damage consistent with a severe frontal impact
As far as I understood the rim was severely damaged.
But ok, letās forget about his case in particular. What I meant was, if one broke his/her wheel, would a hooked/hookless rim matter?
And I am genuinely asking this, because all the noise started with situations like that, which, in my opinion, are inaccurately attributed to hookless rims, as they were a result of a broken part, regardless of the type of construction.
I saw a short video posted yesterday by the Paris Roubaix account with an Israel Premier Tech and a tire blowing off completely after he hit something or had a puncture. IPT rides Black Inck, which I did some research on and appears to be hooked, and I didnāt see 1 line about it.